YaeCCC Variac, 500VA Variable Voltage Transformer,AC Auto Transformer

the VU meter matches the dial labeling but nether of those match actual output voltage. the dial is labeled in increments of 13 volts and for every increment +1v or +2v is added to the actual voltage so at 13v dial setting I get 15v, at 26v dial setting I get 30v, etc. at 130v dial setting I get 148v output. output spikes -1.3v at max output (148v) and -0.6v at near min setting (2v) periodically (~2hz, smooth spike). aside from this spike voltage is +/- 0.1v for about 70% of the time, the other 30% being that spike happening. attached is a multi meter test for the dial sweep. dial was turned from min to max to min at a more or less constant rate a few times. voltage spike happens with my unit at around 25v and its significant. you can see it in the picture. the rest of the transition from min voltage to max is smooth. scale of the graph is 0v-160v mean is 80v. also attached is oscilloscope reading of the output at 2v. my scope is only rated for 10v max and im not going to push it with this unit. shows 60hz +/- 0.1hz with a periodic spike in hz every so often which makes it dip to sub 20hz. spike is super short (a few microsecond or less is my guess, didn't bother to try and catch it on the scope to measure it explicitly.) and happens less than once per second so no big deal. you can see that spike measured in the statistics frame on the oscilloscope image under the Min column, average column is still close to 60z so its not a significant spike. if you care about a spike that short you probably care about the waveform too - scope shows a pretty clean saw waveform, not sine wave. this aint guna be lab gear. all in all, for the price, its fine. its not supposed to be lab equipment and as long as you mind the actual output voltage it should work well. im pretty happy with it. UPDATE: been running 24/7 for 11 months, no issues at all.

Works wonders with my big industrial fans.

Easily the best option when bench top supplies don't cut it. If you're at the point where it's impractical to keep buying larger power supplies, you need one of these. Frankly, they are just awesome. You get a massive range of voltages to play with, and best of all, it's AC! Seriously, this expands the range of devices you can power immensely. And not just Microwave Oven Transformers. But those do totally work 😉. The thing even has about half a Henry of inductance at full tilt, and does hum pretty good if you're pushing the rated power, but personally I consider this an audible saftey feature 🤷. Built pretty good, replaceable fuse slot is nice. Yeah, buy one imo. Makes the wall socket somewhat less scary, and that's pretty great

I just received the unit, and checked the voltages using a multimeter. It delivers a different range than what is shown on the unit. Rather than 0 - 130 VAC it delivers 0 - 150 VAC. I recommend calibrating and putting your own markers using tape so you know what you've got. For example, to get 100 VAC, 110 VAC, and 120 VAC I need to set the dial at around 88, 96, 104, respectively. My wall voltage is 123.4 VAC, so that might be part of the issue -- the unit might be expecting a wall voltage that is lower. But in any case, you should calibrate this according to YOUR home voltages.

Works as described - just be sure to check the AC output for fluctuations as this is AC so incoming power affects the output

Its working good

One of two purchased, both good after 6 mo.

Good coarse adjustment. Definitely not for fine bench work. Voltage jumps +/- 1 volt even after you dial it in. I was trying to calibrate 3 ADC channels and the voltage would change +/- 1V during the 30 second capture. I had to re-adjust this unit for every channel.

Cumple con su función

El indicador de voltaje es muy impreciso, por lo demás excelente